Artificial fabric



Patented Feb. 6, 1934 1 945 533 1,945,538 ARTIFICIAL FABRIC George L.Schwartz, Wilmington, Del., assignor to E. I. du Pont de Nemours &Company, Wilmington, Del., a corporation of Delaware No Drawing.Application May 31, 1930, Serial No. 458,900. Renewed January 19, 1933 8Claims. (CI. 92-40) This invention relates to new and useful imkalinesolution the fibers are thoroughly washed provements in artificialfabrics and more parwith water and are then in the alteredconditicularly to fabrics formed from cellulosic fibers tion, exhibitingthe appearance of having a that have been artificially crinkled bychemical crinkle as compared with their original condition.

treatment and have been impregnated with rub- These cellulose fibers arethen suitably pulped 60 her latex or similar aqueous dispersions ofrubber. and felted. For some purposes it is desirable to In priormethods of preparing artificial fabrics hydrate the pulp before feltinginto paper and to from cellulosic fibers by impregnation with rubthisend the crinkled pulp is beaten while disber solutions in various forms,it has been found persed in water in a standard paper beating ap- 10that fabrics so prepared have had certain undeparatus for a period ofseveral hours, ranging, 65 sirable characteristics, such as stiffness, acharfor p e, from 2 to 12 hOllrS- In this p acteristic of breaking uponflexing or bending ation it is not desired to cut the fibers but merelythe article, a tendency to a poor resistance against to brush them outand hydrate them and to cause abrasion, a tendency for the rubber tooxidize the fibers to exhibit afrayed appearance. Therel5 upon ageing, apoor resistance against tearing, after the fibers are deposited in theform of aweb, 70

and certain other defects. as in known methods of manufacturing paper,

It is an object of this invention to avoid the and the web is thereupondried. aforesaid difiiculties in the preparation of arti- The dried webis then passed into a rubber flcial fabrics, in other words, tomanufacture an latex liquid in order to impregnate it with theartificial fabric from a fibrous cellulosic base rubber latex. Thismaybe performed in d y 7 by impregnation with rubber so that the fabricimpregnating pp The desired P will have the characteristics offlexibility, rea e f th ru er on en will r n e f m a u sistance totearing, resistance to oxidation on 1 to a g as but preferably in theageing, resistance to abrasion, and will furtherneighbor d o 0% n thefinis d Sh et 0 ebmore have the quality of not breaking upon ric. Afterthe impregnation the article is dried 80 bending and flexing the fabric.in order to coagulate the latex, but other methods The article of thisinvention may be manu- 0f o u a h a e yp y Such factured by thefollowing preferred form of proas passing the i p d h t t o a cedure:solution of aluminum sulphate or other coagu- The basic material for thefabric consists of a lating agent. When coagulated with chemical 85fibrous cellulosic material prepared in a special a t th sheets are p dou h w nser manner as more particularly set for in the apor rollers tosqueeze out superfluous liquid and plication of McCormick and SchwartzSer. No. then dried. At the conclusion of the drying oper- 283 145,filed June 6, 1928, of which Patent, ation the sheets are compressed togive afinished 1,857,100 is a continuation in part. A brief deapp a andy be d d Ot w s 90 scription of this process for treating the fibroustreated, according to the usual practices in this cellulose is asfollows: art.

Wood or other suitable fibrous cellulosic pulp The resulting sheet hasexceedingly valuable is prepared in any suitable manner and is thencharacteristics of great utility in the various arts treated withcaustic alkali, for example, sodium for which such an article ofmanufacture is 95 potassium or lithium hydroxide, in aqueoussoluadapted. Among its characteristics may be mention at a concentrationof from 8% to 35% at tioned its great flexibility, its property ofshowroom temperature for a short period of time ining no paper-breakwhen bent or sharply flexed, sufficient to cause gelatinization of thecellulose its strong resistance to tear and resistance to fibers. Thistime treatment is generallyamatter abrasion, and its non-oxidizingproperties. In 100 of only several seconds to thirty minutes, thereference to resistance to tear, it should be more preferred practicebeing to disperse the pulp with particularly stated that theherein-described the caustic without cutting action at high pulp sheetwill offer strong resistance against tearing consistencies (low ratio ofliquor to pulp), such by hand, and when subjected to the standard 59 asis disclosed in the examples of the mentioned Elmendorf tester it willshow a value of between 106 application and patent, in order to minimizethe 850 to 1156 in the case of a sheet manufactured effect of timeaction of the strong caustic on the to contain about 17% rubber andhaving a fibre pulp. The caustic solution, when the pulp is weight of.615 lbs. per 40 inch yard. This parcompletely wet therewith, is dilutedwith water ticular example is given merely to illustrate the to stop thereaction. On removal from the altype of fibrous cellulosic-rubber sheetmanufac no tured by this process, and it will be understood that, wheresheets of other specific fibre weights are made with other percentagesof rubber content, the figures on the Elmendorf tester will, of course,vary with those herein given but will be of the same order ofexcellence. A sheet of the character Just described will have athickness of about .025inch, and it will accordingly be seen that such asheet represents a standard article of manufacture useful forbookbinding, base for linoleum, base for wall coverings, auto topmaterials, auto interior coverings, furniture coverings, and many othersimilar and analogous uses wherein fabrics find their employment. It hasalso been found to be useful for preparing products used in theconstruction of shoes such as soft toe boxes, inner soles, liners, etc.It is furthermore found that the fabric herein disclosed cuts easilylike leather without leaving a frayed edge. I

A base material made of artificially crinkled fibers as herein disclosedhas unusual strength 4 in view of its extreme porosity. Because of thisstrength and high absorbency, it is peculiarly adapted to impregnationwith latex for the production of vulcanized or unvulcanized sheetshaving remarkable strength and tear resistance as compared with aproduct in which this base material is impregnated with solutions ofcoagulated rubber in organic solvents. In regard to ageing qualities,unvulcanized and coagulated rubber latex ages extremely well. However,the ageing may be afl'ected favorably or adversely by the materials withwhich the rubber is associated. As previously noted, the product of thepresent invention has exceptional ageing qualities and it appears,therefore, that the specially prepared base exercises a favorableinfluence in maintaining the rubber in its non-oxidized state.

It should also be pointed out that this particular fabric is notlaminated, but consists of a single deposited sheet impregnated withrubber. It has been found, however, that a laminated sheet may be madeby gluing together sheets as herein described or by putting on amultiple deposit during the paper-making step and impregnating the latexinto the multiple deposits. Furthermore, instead of laminating,- thesheet may be made thicker than herein described so as to constitute asingle deposited article equalling in its thickness a multiple-depositedor laminated sheet, and thereby securing advantages in flexibility andstructural strength not possessed by laminated sheets. The latter is aparticular advantage of this invention.

many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that I do not limit myself to the specific embodimentsthereof except as defined in the appended claims.

I claim:

1. An article of manufacture comprising a web of artificially crinkledfibrous cellulosic material impregnated with rubber latex coagulatedtherein, said article being flexible, exhibiting no paper-break, andhaving strong resistance to tear and strong resistance to abrasion, saidweb being substantially identical with the web obtained by dispersingpaper pulp with 8% to 35% sodium hydroxide solution at room temperature,promptly washing out the caustic and felting the pulp.

2. The invention in claim 1 wherein the cellulosic material exists inthe condition of hydrated, frayed, beaten fibers.

3. The process of manufacturing an artificial fabric comprisingdepositing a web of artificially crinkled cellulosic material,impregnating it with rubber latex, coagulating the latex, and drying thesheet.

4. The process of manufacturing an artificial fabric which comprisestreating cellulose fibers in pulp form with caustic alkali having aconcentration of between 8% and 35%, removing the caustic after a timenot longer than 39 minutes, dispersing the crinkled fibers so preparedin water, depositing a web thereof, impregnating the web with rubberlatex, and drying the sheet.

5. The process of manufacturing an artificial fabric which comprisestreating wood pulp at high pulp consistences. with caustic alkali havinga concentration of between 8% and 35%, removing the caustic after a timenot longer than 30 minutes, dispersing the crinkled fibres so preparedin water, depositing a web thereof, impregnating the web with rubberlatex, and drying the sheet.

6. The process of manufacturing an artificial fabric which comprisestreating cellulose fibres in pulp form with caustic alkali having aconcentration of between 8% and 35% for a time not longer than 30minutes, washing the treated fibres and dispersing them in water,beating the fibres in the water for from 2 to 12 hours to brush them outand hydrate them without cutting them, depositing'a web thereof,impregnating the web with rubber latex, and drying the sheet.

7. The product produced in accordance with the process set forth inclaim 5.

8. The product produced in accordance with the process set forth inclaim 6.

GEORGE L. SCHWARTZ.

